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Author Topic: Yo................ Vincenzo.......................  (Read 161571 times)
AC5UP
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« Reply #90 on: September 01, 2012, 11:11:21 AM »

The GE you linked to was a very popular radio back in the day. Could be found at all the discount chains like Kresge's and Sears for a decent price, looked good, and it had FM before FM was cool. GE made decent radios back in the day but I have a strong hunch that one was made in Japan. Probably one of the more successful of the early imports under a US brand name.

As for the Zenith, that's a tough call for me as I am genetically cheap and some Goodwill stores can be a little high on their shipping & handling charges. I haven't done any eBay in close to ten years because I ran into too many sellers who tried to make their dime on the freight instead of the goods. From their perspective the bid is maybe a good deal for them, but the freight is always whatever they can squeeze from the seller.

Anyway... The Zenith looks to be complete and in near-mint condition. It was not a low end model and there's a good chance it was made in Illinois. If I saw it at a swap meet I wouldn't go over $15 assuming the condition is as good as I think it is. But from Goodwill I might go $25 total (bid plus freight) as I'll get a better deal there than through eBay and I'll probably never see one at a local swap or thrift shop. I'm a casual observer and I don't think that radio will see much bid pressure, but from a collector's standpoint the Zenith Royal series were regarded as above average in performance and it's rare to see a 1966 vintage leather case with no scuffs or open seams. The battery holder looks like six C or D cells for long play times and is in mint condition. Collectors tend to go orgasmic when they see Conelrad marks on a dial, I went orgasmic when I saw what looks like a real tuning condenser with a metal frame instead of a common miniature plastic jobbie.

Put $10 or $15 on it and see what happens. Since it's in Johnstown, PA your shipping shouldn't be too horrendous on nine pounds to NJ and you might get lucky....  (?)
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AC5UP
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« Reply #91 on: September 01, 2012, 12:19:44 PM »

Ooooooops................

...but the freight is always whatever they can squeeze from the seller.

Should read: " squeeze from the buyer ".   Moi Mal.
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N4NYY
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« Reply #92 on: September 01, 2012, 02:00:28 PM »

GE radio is DOA. I Dremeled the rust off the battery tabs, Deoxit the pot, and no dice. I asked on Antiques Radio forum about these old Transistor radios, and they said that they almost always need recapping because the caps always dry out. Dead give away is the audio coupling electrolytic, which leads to a fully DOA radio.

Still looking for the damn schematic. 
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AC5UP
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« Reply #93 on: September 01, 2012, 02:42:06 PM »

Best bet for a schematic would be to surf through the last of the Beitman books and look for a similar model. The Rider manuals from Nostalgia Air won't help because the radio is too new. Beitman goes through the 60's but their model coverage did get a bit spotty towards the end and the last few books offer almost nothing beyond a squidmatic.

Look at enough schizmatics and you'll notice patterns where Japanese transistor radios tended to look a lot like US transistor radios because of all the outsourcing. There wasn't much variation from one brand to another and most US brands were built by Toshiba / Hitachi / Sanyo, etc. SONY and Matsushita (Panasonic) were big enough to develop their own US distribution but the rest contracted work for RCA, Philco, Magnavox, etc. There was a time when you did not try to market anything with a name like Mitsubishi as one of their more famous products was a military aircraft named the A6M Zero-Sen forever associated with a Sunday morning in December at Pearl Harbor.........

http://en.wikipedia.org/wiki/A6M_Zero                 <cough!>

The AM Zenith's were unique in that they had an extra stage of amplification in the IF, but aside from that once you understand the Zen of Japanese radios you won't need an exact squidmatic. AM / FM, 15 transistors, was I right that the innards look imported?
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N4NYY
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« Reply #94 on: September 01, 2012, 02:42:33 PM »

Best bet for a schematic would be to surf through the last of the Beitman books and look for a similar model. The Rider manuals from Nostalgia Air won't help because the radio is too new. Beitman goes through the 60's but their model coverage did get a bit spotty towards the end and the last few books offer almost nothing beyond a squidmatic.

Look at enough schizmatics and you'll notice patterns where Japanese transistor radios tended to look a lot like US transistor radios because of all the outsourcing. There wasn't much variation from one brand to another and most US brands were built by Toshiba / Hitachi / Sanyo, etc. SONY and Matsushita (Panasonic) were big enough to develop their own US distribution but the rest contracted work for RCA, Philco, Magnavox, etc. There was a time when you did not try to market anything with a name like Mitsubishi as one of their more famous products was a military aircraft named the A6M Zero-Sen forever associated with a Sunday morning in December at Pearl Harbor.........

<cough!>


I took a quick look before and will look again. I found a site for the squidmatic, but the cost would be more than the value of the radio. So I will do that, worst case scenario. I would rather look for a free one.

Apparently, there are numerous similar models. Problem is that I do not know anything about it, so I am waiting some responses to see which they are.
The AM Zenith's were unique in that they had an extra stage of amplification in the IF, but aside from that once you understand the Zen of Japanese radios you won't need an exact squidmatic. AM / FM, 15 transistors, was I right that the innards look imported?

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AC5UP
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« Reply #95 on: September 01, 2012, 03:03:45 PM »

A coupla' years ago I picked up a buck nekkid AM / FM tube chassis at the annual antique radio club meet & swap that had absolutely no model or manufacturer's ident on the chassis. None, zero, nada, not so much as a date code or serial number. Which is one reason why the seller let it go reeeel cheap............ Which attracted me like a magnet.

Had I grown up in New Jersey I'd have given up the squidmatic concept on the spot, but instead, I took a few hours on a Sunday afternoon to study the chassis for landmarks. Like the tube numbers to determine the approximate age and a curious detail in the audio PA: Instead of the push-pull 6V6's being next to each other, the chassis has a 5Y3 between them. And, the FM dial scale is marked by FCC channel number, not frequency. Those two clues were all I needed.

I have both the complete Rider's Perpetual and Beitman library downloaded on my local drive and it took less than an hour to find a chassis with a 5Y3 between the PA tubes and FM alignment procedure that translated channel numbers to signal generator frequency. Taa-Daa... Rare bird, itza 1948 Farnsworth / Capehart chassis from a radio / phono console.

Study the transistor numbers and draw a little road map to the chassis. Look for oddities like a big-ass condenser near the audio output or the lack of a driver transformer. The classic Japanese transistor radio had an interstage transformer between the 1st audio transistor(s) and the push-pull output, but others used a two transistor phase inverter like you see in tube circuits.

Learn that about the radio and you should find something similar. GE sold a buttload of those.
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N4NYY
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« Reply #96 on: September 01, 2012, 04:51:03 PM »

Got the squidmatic. A bunch of people replied, and they all said the same thing. Replaced all the caps (only 7), because that is the most common problem in transistor radios. They dry out and then are done.
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AC5UP
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« Reply #97 on: September 01, 2012, 05:03:02 PM »

Dude:

Just for the helluvit I did some surfing and could not find a free squidmatic. Nor anything close in Biteme's Most Popular. As suspected the radio is definitely Japanese, but the circuit flow is pretty obvious by looking at the PC board:

http://www.radiomuseum.org/r/general_el_p975p_97.html
http://www.radiomuseum.org/images/radio/general_electric_co/p975_672749.jpg

RF section upper right, local oscillators left of there above the push-push bandswitch, IF runs down the left side of the board. AF starts centered above the speaker magnet and kinda' wanders toward the lower right. Note the two transformers, interstage (P-P phasing) and output. Dead giveaway for audio.

Any doofus with an Extech should be able to get that one playing again.

BTW: Picked up an interesting trick while surfing the Biteme books from '63 through '67.......... Always start a service session on a battery operated portable radio with a quick check of the idle current draw. How do you do that? Turn the radio off, check the battery voltage to be sure they're up to rated voltage, minimize the volume control if the power switch is separate, then hang your DC milliammeter across the power switch.

Should read 20 to 25 mils, typical. If much higher the most likely cause is an audio output transistor gone bad.

Cool Tip, ehhhhhhh?  Try it on the Geeeeee I'm Dead radio just so you can say you did.   Grin
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N4NYY
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« Reply #98 on: September 01, 2012, 05:08:53 PM »

Damn odd values. 200uf, 250uf, 3 uf. I can replace with 220, 270, 3.3, or 4.7. But I do not think I have those values in my stash. May have to place an order.
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AC5UP
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« Reply #99 on: September 01, 2012, 07:07:32 PM »

That reminds me........... I was cleaning the garage last week and..................   Grin

BTW:  If you ever want to build up a pile of lo-volt electrolytics on the cheap, visit your local thrift shop(s) and keep an eye open for a late 80's VCR. You know, the large, heavy kind with no Hi-Fi and probably not stereo. Remember the old-school VCR's with an adjustment wheel for each channel? That's the kind you want. The store will be glad to see it go even though you'll spend $5.00 or less and you'll score a possibly useful power transformer plus a buttload of small electrolytics and transistors. The 2SC945 is Tokyo's idea of a 2N2222 and the old VCR's used them in droves. Takes only an hour or so to tear one down and the pile of parts you pull will work out to a only few cents apiece.

You do not want a newer, nicer, lighter VCR for this exercise as they have almost no parts inside.

I think you have a condenser checker and if it's like mine you can run through a pile of them in no time at all. I've been recycling parts for many moon and last week swapped out a beer can sized power-lytic that was beyond the meter's upper range. Charged it to 20 VDC as a test and 24 hours later it still measured 12 volts, so I'm calling it good enough to use.
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N4NYY
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« Reply #100 on: September 02, 2012, 06:07:56 AM »

Nelson,

Here is a quick note on the  Zenith 755:

http://radiojayallen.com/zenith-royal-700-series-the-lunchbox-radios/

"The first model, the LF had a large plastic handle which contained the ferrite rod and swiveled for best reception. That’s a great feature, however it was soon realized that when the handle was grasped, the hand capacitance effect detuned the circuit and diminished reception, so the LF was soon replaced with the LG which moved the ferrite rod back inside the cabinet."

LOL
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AC5UP
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« Reply #101 on: September 02, 2012, 06:48:13 AM »

Whoa.......... Most excellent link on the 755 lunchbox radios. I knew the Zenith Royal's were above average in design sophistication by the schematics in Biteme's Most Often Needed, but I had no idea how expensive they were in terms of constant dollars. No wonder they're kinda' rare, and HELL YES I'm keeping an eye on the Goodwill auction.

Funny to remember that today a radio is a minor expense at Wally World, but back in the day they were not cheap at all. Look at the vintage advertising and you'll find a floor console from the late 30's was a thousand (constant) dollar item (or better) when new. They offered excellent reception and sound quality at a price that was considered the accepted cost of admission to high end performance. Even today people still marvel at how good they sound when properly restored.

OTOH, there were plenty of radio shows worth listening to back then, so in a way you got what you paid for.

Both then and now.     Tongue
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N4NYY
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« Reply #102 on: September 02, 2012, 08:12:34 AM »

Dammit. I cut the tuning string with my soldering iron when I was removing a cap. Damn, these transistor version are packed in like sardines. Any, I still have the string you sent me. It is thicker, but I am wondering if I could use it.
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AC5UP
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« Reply #103 on: September 02, 2012, 08:54:30 AM »

http://www.intikemo.com.br/wp-content/uploads/2011/05/HomerSimpson36.gif

...........and some people still wonder why I make doofus jokes with you.

Next time you're out and about keep an eye open for a good fabric store. Drop in to check out their carpet & upholstery thread offerings. Nylon is strongest, but Polyester is far less likely to stretch:  http://www.ehow.com/about_5385084_nylon-vs-polyester-thread.html

PS:  You're a doof, but you're our doof.  If that's the worst thing that happens to you today you got off easy.   Roll Eyes

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N4NYY
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« Reply #104 on: September 02, 2012, 09:09:33 AM »

http://www.intikemo.com.br/wp-content/uploads/2011/05/HomerSimpson36.gif

...........and some people still wonder why I make doofus jokes with you.

Next time you're out and about keep an eye open for a good fabric store. Drop in to check out their carpet & upholstery thread offerings. Nylon is strongest, but Polyester is far less likely to stretch:  http://www.ehow.com/about_5385084_nylon-vs-polyester-thread.html

PS:  You're a doof, but you're our doof.  If that's the worst thing that happens to you today you got off easy.   Roll Eyes



LOL. FWIW, I went to the eye doctor last Dec and she said my near sight is failing. Well, after not working on a radio for several months, she is right. Everything close is blurry.
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